Dog Skin Conditions and Disorders: Pictures, Causes and Treatment

Dog Skin Conditions by Body Area

Show photo: Superficial bacterial skin infection on the abdomen of a Labrador Retriever

Superficial bacterial skin infection (pyoderma) on the abdomen of a Labrador. Source: Washington State University College of Veterinary Medicine.

Appearance and What It Can Mean

The pattern of a skin problem, as well as its location, helps narrow down the cause.

Dog Skin Condition Pictures: Common Lesions Explained

Veterinarians describe skin problems using standard terms. Knowing these helps you describe what you see and understand your vet's findings. A single dog often has several types at once.

Show photo: Papule on dog skin

Papule: a small, solid, raised red bump under about 1 cm across. Common with bacterial infection, flea bites, sarcoptic mange and allergies.

Show photo: Pustule on dog skin

Pustule: a small bump filled with pus, like a pimple. Most often a sign of bacterial skin infection (pyoderma); less commonly an autoimmune disease such as pemphigus foliaceus.

Show photo: Vesicle on dog skin

Vesicle: a small blister filled with clear fluid. Uncommon in dogs and short-lived; causes include autoimmune and inherited skin diseases, burns and some drug reactions.

Show photo: Wheal or hive on dog skin

Wheal (hive): a smooth, raised swelling that appears and fades quickly. Hives (urticaria) are usually caused by insect stings or bites, vaccines, medications or foods. Sudden swelling of the face or trouble breathing is an emergency.

Show photo: Nodule on dog skin

Nodule: a solid lump larger than about 1 cm that extends into deeper skin layers. Causes include deep infection, inflammatory reactions (granulomas), cysts, calcium deposits and tumors.

Show photo: Tumor on dog skin

Tumor: a large mass. The word describes size, not cancer; many skin masses are benign. See dog skin tumors for details.

Show photo: Ulcer on dog skin

Ulcer: a sore where the full thickness of the outer skin layer is lost, exposing the deeper layer beneath. Causes include deep infection, injury, burns, autoimmune disease and some cancers. Ulcers need a vet visit.

Show photo: Epidermal collarette on dog skin

Epidermal collarette: a ring of peeling scale left behind when a pustule bursts, often with a darker center. It is a classic sign of superficial bacterial skin infection.^1,6

Crusts: dried pus, blood or skin cells stuck to the surface. Honey- to brown-colored crusts with hair embedded in them are typical of bacterial skin infection.

Common Dog Skin Conditions

Environmental allergy (atopic dermatitis)

An inherited tendency to react to pollens, dust mites and molds, combined with a weakened skin barrier. Signs usually begin between 6 months and 3 years of age and cause itching of the face, ears, paws, front legs, armpits, belly and groin, often with repeated ear and skin infections. It is managed, not cured;^2,10 see itch treatment and allergy immunotherapy below. Read more about dog allergies.

Flea allergy dermatitis

Some dogs react strongly to flea saliva, so even a few bites cause intense itching over the lower back, tail base and back of the thighs. Year-round flea prevention for every pet in the home is the cornerstone of treatment.

Food allergy

Food allergy causes year-round itching, often of the face, ears, paws and rear end, sometimes with soft stools. The only reliable test is a strict elimination diet trial (see treatment); blood, saliva, hair and skin tests cannot diagnose food allergy.³

Bacterial skin infection (pyoderma)

Most skin infections are an overgrowth of the staph bacteria that normally live on a dog's skin, most commonly Staphylococcus pseudintermedius. Superficial infections cause red bumps, pustules, crusts and peeling rings; deep infections cause painful sores and draining tracts. Pyoderma is almost always secondary to another problem, most often allergy, so the infection will keep coming back unless the underlying cause is controlled.^1,6

Antibiotic resistance is a growing concern. In one U.S. study, the share of S. pseudintermedius samples that were methicillin-resistant (MRSP) rose from 28% in 2010 to 80% in 2020, and dogs that received antibiotics recently are at higher risk.⁶ Dogs can carry MRSP on their skin for months after an infection clears and can pass it to other pets and, occasionally, to people.⁶ See treatment for what this means for your dog.

Yeast infection (Malassezia dermatitis)

Overgrowth of normal skin yeast causes greasy, red, itchy and often smelly skin, commonly in the ears, between the toes, under the neck and in skin folds. Like bacterial infection, it is usually secondary to allergy or hormonal disease. Learn more about yeast infections in dogs.

Ringworm (dermatophytosis)

A fungal infection, not a worm. It typically causes circular patches of hair loss with scaling and may not itch. It is contagious to people and other pets. A Wood's lamp is only a screening tool; diagnosis is confirmed by fungal culture or PCR testing.⁴

Mange

Sarcoptic mange (canine scabies) is caused by burrowing mites. It is intensely itchy, often starts on the ear edges, elbows and belly, and is highly contagious to other dogs. People in contact can get a temporary itchy rash, although the mites cannot complete their life cycle on humans.⁹

Demodectic mange is caused by an overgrowth of Demodex mites that live in hair follicles of all dogs. It is not contagious; puppies acquire the mites from their mother in the first days of life. It causes patchy hair loss, often around the face and paws, and is usually only mildly itchy unless infection develops. Demodex in an adult dog can signal an underlying illness or medication that suppresses the immune system.⁵ See dog mange symptoms.

Hormonal (endocrine) skin disease

An underactive thyroid (hypothyroidism) or overactive adrenal glands (Cushing's disease) can cause thinning hair, symmetrical hair loss, thin skin and recurrent infections, usually without much itch. Blood tests confirm the diagnosis, and the skin improves once the hormone problem is treated.

Autoimmune skin disease

The immune system attacks the skin. Pemphigus foliaceus, the most common, causes pustules and thick crusts on the face, ears and paw pads. Discoid lupus mainly affects the nose. A biopsy is needed for diagnosis, and treatment is long-term.

Seborrhea

Canine seborrhea is a disorder of how the skin renews its outer layer, causing flaking, dry or greasy skin and a rancid odor. Primary seborrhea is inherited, starts young and is seen in breeds such as American Cocker Spaniels, English Springer Spaniels, Basset Hounds and West Highland White Terriers. Most cases are secondary to allergies, parasites, hormonal disease or poor nutrition and improve when the cause is treated. Medicated shampoos help control signs.⁸

Lumps, cysts and skin cancer

Most lumps in dogs are benign, such as fatty tumors and cysts, but skin is also a common site of cancer, including mast cell tumors that can look like harmless bumps. You cannot tell a lump's type by looking or feeling. Ask your vet to sample any new, growing or changing lump. See dog skin tumors.

Treating Dog Skin Conditions

The most effective treatment is the one that addresses the underlying cause. Itch relief and infection treatment buy comfort while that cause is found and controlled. Always work with your veterinarian: several conditions look alike, and some treatments that help one condition make another worse.

Medicated Shampoos and Topical Therapy

Medicated bathing treats superficial infections directly and is now preferred over antibiotic pills for many cases, because a recent controlled study found topical chlorhexidine as effective as oral antibiotics over four weeks.⁶ For best results, lather and leave the shampoo on for about 10 minutes before rinsing. During an infection, bathe 2–3 times a week until about a week after the skin looks normal, or as your vet directs.⁶ Wipes, gels and sprays suit small areas and are usually used daily.

Coal tar shampoos are now rarely recommended and are toxic to cats. Never use dog medicated or flea products on cats without checking with your vet.

Bacterial Infections and Antibiotics

Current international guidelines (ISCAID, 2025) recommend:¹

• Topical therapy first for most superficial infections.
• Cytology to confirm infection before treating, and a bacterial culture for deep or recurrent infections, infections that don't respond within about two weeks, or dogs that have had resistant infections or recent antibiotics.
• Shorter courses when pills are needed: roughly 2 weeks for superficial infection and 3 weeks for deep infection, followed by a recheck, rather than extending treatment for weeks "just in case." Chronic deep infections can still take longer.¹

Give antibiotics exactly as prescribed, don't save leftovers for next time, and keep in mind that preventing the next infection means controlling the underlying allergy.

Ringworm Treatment

Ringworm is treated with oral antifungals (itraconazole or terbinafine are preferred), whole-body topical therapy such as lime sulfur dips or miconazole-chlorhexidine shampoo twice weekly, and thorough cleaning of the home to remove infectious spores. Treatment continues until follow-up fungal cultures are negative. Older drugs such as griseofulvin and ketoconazole are now used less often because of side effects.⁴

Itch Relief Medications

No single drug works for every itchy dog. Your vet will choose based on the cause, your dog's age and health, and how quickly relief is needed.

Never give your dog human anti-itch, pain or allergy medications without veterinary advice; some are toxic to dogs.

Allergy Immunotherapy (Allergy Shots or Drops)

Immunotherapy gradually desensitizes your dog to the specific pollens, mites or molds identified by allergy testing. It is the only treatment that targets the cause of environmental allergy. About 60–70% of dogs improve noticeably, although only a minority can be managed on immunotherapy alone. Improvement often takes 6–12 months, so it should be continued for at least a year before judging results.¹⁰ It is available as injections or as drops under the tongue (sublingual), and other itch medications can be used while it takes effect.

Food Allergy: The Elimination Diet Trial

To test for food allergy, feed a prescription hydrolyzed-protein diet or a diet with a protein your dog has never eaten for at least 8 weeks, which identifies more than 90% of food-allergic dogs.³ During the trial your dog must eat nothing else: no treats, flavored medications or chews, table food or dental treats. If itching improves, food allergy is confirmed by switching back to the old food and watching for a flare. Hydrolyzed diets such as Purina Pro Plan Veterinary Diets HA Hydrolyzed break proteins into pieces too small to trigger most allergic reactions. Over-the-counter "limited ingredient" foods are not reliable for a diagnostic trial because they can contain traces of other proteins. See also sensitive skin dog food.

Parasites

Skin parasites such as fleas, mange mites, lice, ticks and Cheyletiella are a leading cause of itch. Treatment has changed considerably in recent years.

Fleas: Treat every dog and cat in the home year-round with a product your vet recommends, and wash bedding and vacuum frequently, because most of the flea population lives in the environment as eggs and larvae. Dogs with flea allergy need strict, uninterrupted prevention.

Mange: Treatment continues until two consecutive skin scrapings a month apart are negative, which often takes several months for demodectic mange. Amitraz (Mitaban) dips, once the standard demodex treatment, are no longer available in the U.S.¹¹

Canine Dry Skin

Dry, flaky skin can be caused by low humidity, over-bathing or harsh shampoos, poor-quality or unbalanced diets, allergies, parasites such as Cheyletiella, and hormonal disease. Start by ruling out parasites and medical causes with your vet. A complete and balanced diet, omega-3 fatty acid supplements, moisturizing or oatmeal shampoos and leave-on conditioners can help. Persistent flaking should be checked, because it is often a sign of an underlying problem rather than simply dry skin.

Frequently Asked Questions

What are the most common skin conditions in dogs?

The most common are allergies (environmental atopic dermatitis, flea allergy and food allergy), bacterial skin infections (pyoderma), yeast overgrowth and parasites such as fleas and mange mites. Most bacterial and yeast infections are secondary to an underlying allergy, so lasting control means finding and managing that cause.

How do I tell what skin condition my dog has?

Start with three clues: where on the body the problem is, whether it itches, and how it looks (red bumps, rings, greasy skin, hair loss or lumps). The body area and appearance tables above show what each pattern usually means. Many conditions look alike, though, and dogs often have more than one at once, so a vet confirms the cause with quick in-clinic tests such as skin cytology, skin scrapings and flea combing.

What does dermatitis look like on a dog?

Dermatitis usually shows as red, inflamed skin with scratching, licking or chewing. You may see hair loss, small red bumps, crusts or scaling. Over time the skin can darken and thicken. Allergic dermatitis typically affects the face, ears, paws, armpits, belly and groin, while flea allergy concentrates over the lower back and tail base.

What does a bacterial skin infection look like on a dog?

Superficial bacterial infection (pyoderma), usually caused by staph, shows up as small red bumps, pimple-like pustules, crusts and circular rings of peeling skin, most often on the belly, armpits and groin. In short-coated dogs it can look like patchy, "moth-eaten" hair loss. Deeper infections cause painful swelling, bloody crusts and draining sores and need prompt veterinary care.

What does fungal dermatitis look like on a dog?

Ringworm often causes round patches of hair loss with scaling or crusting and may not itch. Yeast (Malassezia) dermatitis causes greasy, red, itchy and often smelly skin, commonly in skin folds, ears, paws and under the neck. A vet confirms ringworm with fungal culture or PCR and yeast with cytology.

How can you tell if a dog skin infection is fungal or bacterial?

You usually can't by looking, and dogs often have bacteria and yeast at the same time. Your vet presses tape or a slide to the skin and examines it under the microscope (cytology), which shows bacteria or yeast within minutes. Ringworm needs a fungal culture or PCR test. Getting this right matters because antibiotics do nothing for yeast or ringworm, and antifungals do nothing for bacteria.

What does a cancerous skin lesion look like on a dog?

There is no single look. Warning signs include a lump that grows quickly or changes size, shape or color; a lump that is firm and fixed in place; a sore that bleeds, ulcerates or will not heal; and dark growths in the mouth or on a toe or nail bed. Mast cell tumors, the most common skin cancer in dogs, can look like a harmless bump or insect bite. Only a needle sample or biopsy can tell benign from malignant, so have any new or changing lump checked.

Why is my dog's skin turning black?

Darkening (hyperpigmentation) is most often the skin's response to long-term inflammation from allergies, infection or friction, and it usually fades once the underlying problem is controlled. Less often it is caused by hormonal disease. See dog black skin.

What is the most common autoimmune skin disease in dogs?

Pemphigus foliaceus. It causes pustules that quickly break into thick crusts on the bridge of the nose, around the eyes, on the ear flaps and on the paw pads, sometimes spreading over the body. Akitas and Chow Chows are predisposed. A skin biopsy confirms it, and it is usually controlled with long-term immune-suppressing medication.

Which dog breeds are most prone to skin problems?

Breeds prone to allergies include Labrador and Golden Retrievers, West Highland White Terriers, French and English Bulldogs, Boxers, German Shepherds and Shih Tzus. Wrinkly breeds such as Bulldogs, Pugs and Shar-Peis get skin-fold infections, Cocker Spaniels and Basset Hounds are prone to seborrhea and ear disease, and German Shepherds are prone to deep skin infections. Mixed-breed dogs can develop all of these too.

Are dog skin conditions contagious to people?

Some are. Ringworm and sarcoptic mange can spread to people, and antibiotic-resistant staph can occasionally pass between dogs and owners. Wash your hands after handling affected skin and avoid face-licking during an active infection. Demodectic mange, allergies, seborrhea and hormonal skin disease are not contagious.

What can I give my dog for itchy skin?

Start with a vet visit, because the right treatment depends on the cause; fleas, infection and mites must be ruled out first. Prescription options include Apoquel, Zenrelia, Cytopoint injections, cyclosporine and short courses of steroids. Antihistamines and omega-3 fatty acids help only modestly. Never give human medications without veterinary advice.

Can a dog skin infection go away on its own, or be treated at home?

A very mild patch sometimes settles, but most skin infections return or worsen unless the underlying cause, usually allergy or parasites, is treated. At home you can keep the area clean and dry, stop licking with a cone or shirt, and bathe with a chlorhexidine shampoo left on for 10 minutes. Avoid human antibiotic creams the dog can lick off, concentrated tea tree oil (toxic to dogs) and repeated hydrogen peroxide or alcohol, which damage healing skin. See a vet if it spreads, oozes, smells, is painful or has not improved within a week or two.

When should I take my dog to the vet for a skin problem?

See a vet promptly for open or draining sores, rapidly spreading redness, a new or changing lump, skin problems with fever, lethargy or poor appetite, severe itching that disturbs sleep, or anything that has not improved within one to two weeks.

Brochures on Canine Skin Problems: